Addon domains with Google Cloud?

I've matched all the IP's from my VM instance from Google Cloud, the domain registar, and on Cpanel. WHM works, and I can add Cpanel. Although it's not possible to add addon domains, (Unless I turn the security off) Although the domain obviously doesn't actually function as it still has the IP issue. What I noticed with Gcloud for each DNS Cloud domain you create, it will make a new nameserver. The same but with a new letter, like a,b,c,d. ns-cloud-a1.googledomains.com - WHM - Main domain. ns-cloud-b1.googledomains.com - Cpanel Primary domai ns-cloud-c1.googledomains.com - addon domain 1. and so on... If I change them to all A1 so they're match, it does bring up a warning, not sure if that's a superficial warning or not. Either way, i've tried using them as they are and by setting them all to 'a' and I still get the same issue. I've also tried to create my own nameserver, for example, ns1.example.com But the domain registar tells me to change it on the parent and won't let me. Not sure what the parent is, I assumed on the DNS Gcloud, although, changing that makes no difference, still won't let me change it on domain registar, and still won't let me add addon domains to Cpanel. I've been using Cpanel as a customer from other hosting companies for 20 years as a end user. But I am new as host. So there seems to be multple methods, not sure which is the best or the right, and then within that, you have to do a string of things to make it be right, It's like layers within layers, but if you mess just one little thing up everything doesn't work. Unfortunately all the tutorials tell you how to do. X, Y and Z, but not X+Y+Z together. I know how to make cpanel, I know how to addon domains, I know how to change nameservers, unfortunately all the tutorials tell you how to do these things. They won't tell you how to do them in sync together and actually make them work specially with Gcloud, WHM, Cpanel, LCN.